1. Field of Invention
The present invention relates generally to diesel exhaust fluid systems, and more specifically, to diesel exhaust fluid filling and storing systems.
2. Description of the Related Art
In conventional diesel engine systems, Diesel Exhaust Fluid (DEF) is frequently used as an additive in Selective Catalytic Reduction (SCR) emission systems, whereby nitrogen oxides (NOx) are converted into diatomic nitrogen, water, and carbon dioxide. DEF systems known in the art typically include two discrete systems: a DEF storage system mounted to a diesel-powered machine, and a DEF supply system used to re-fill the DEF storage system. Because DEF is consumed when the diesel engine runs, the DEF storage system must be designed so as to cooperate with the DEF supply system such that the DEF storage system can be re-filled when needed.
SCR systems are sensitive to contamination and, as such, DEF storage systems must be filled carefully. To this end, DEF storage systems and DEF filling systems must each be designed so as to prevent exposure to contaminants. Further, the type of DEF most commonly used in the art is an aqueous solution consisting of 32.5% urea and 67.5% deionized water. This solution has a relatively high freezing temperature of 11° C. and expands when frozen. As such, DEF storage systems also typically include some sort of heating or thawing system to either prevent DEF from freezing, or to thaw the DEF after the diesel engine is started. Consequently, DEF storage systems must be designed in such a way that they do not crack or leak if the DEF freezes, as a cracked DEF storage system could expose the DEF to contamination and could lead to DEF leaking into the environment.
Conventional DEF storage systems known in the art typically include some type of storage tank mounted to the diesel-powered machine. The storage tank stores DEF for selective injection into diesel-powered machine's exhaust stream. The storage tank is often mounted on the diesel-powered machine in such a way that it is relatively difficult to gain access to. As such, DEF storage systems also typically include a receiver spaced from the storage tank and mounted somewhere on the diesel-powered machine that is relatively easier to access. The receiver is connected to the storage tank by a supply line routed within the diesel-powered machine, and is adapted to connect the DEF storage system to the DEF supply system.
DEF supply systems know in the art typically include a main supply tank filled with DEF, a pump connected to the main supply tank, a nozzle adapted to connect to the receiver of the DEF storage system, and a feed line that extends in fluid communication between the nozzle and the pump. Thus, when the DEF storage system runs low and needs to be re-filled, the nozzle can be connected to the receiver of the DEF storage system and the pump can subsequently transfer DEF from the main supply tank to the storage tank of the DEF storage system.
Each of the components of a DEF system of the type described above must cooperate to effectively fill a storage tank on a diesel-powered machine. In addition, each of the components must be designed so as to enable the storage tank to be filled quickly and efficiently. Further, each of the components must cooperate so as to protect against DEF contamination and DEF leaking into the environment. While the DEF systems known in the related art have generally performed well for their intended purpose, there remains a need in the art for a DEF system that has superior operational characteristics, provides simple, reliable, and quick filling of a storage tank, and is designed in such a way so as to enable the DEF storage system to be used in harsh environments without the risk of leaking or exposure to contaminants.